Manufacture of vacuum apparatus



Ap 9, 1946. v M. P. WILDER MANUFACTURE OF VACUUM APPARATUS 2Sheets-Sheet l Filed July l1, 1944 Omi-..0 S

gmc/WIM April 9, 1946. M P. WILDER 2,398,340

MANUFACTURE OF VACUUM APPARATUS Filed July ll, 1944 2 Sheets-Sheet 2Patented Apr. 9, 1946 MANUFACTURE OF VACUUM APPARATUS Marshall P.Wilder, Berlin, Conn., assigner to Remington Band Inc., Buffalo, N. Y.,a corporation o! Delaware Application July 11, 1944, Serial No. 544,429

(Cl. S16-26) 3 Claims.

This invention relates to a method and apparatus for the manufacture oivacuum tubes, particularly those used for electron emission of allkinds, including X-ray.

The invention is directed to a method and apparatus that provides foreliminating the disadvantages experiencedin prior methods and apparatusand provides for more eillcient processing of vacuum tubes, provides fora larger output of processed tubes compared with previous methods andapparatus, eliminates the necessity for having operators who areeilicient in several dif.. ferent skills and provides for employingoperators with more limited skill.

The invention further comprehends the provision of apparatus that isarranged and constructed for more convenient operation, apparatusarranged at a plurality of stations, having other portions of theapparatus arranged so that it may be moved from one station to anotherfor facilitating the treatment of vacuum tubes through severaldiil'erent steps or stages in a more eiilcient manner for savingtime,obtaining greater production and reducing the cost of processing vacuumtubes. For example, the invention provides a dolly carrying a pumpingsystem including a fore pump, a diii'usion pump, a manifold andtubulations connected together and having the tubes secured to thetubulations for conveying the tubes while being evacuated from onestation to another for baking, high frequency and electrical treatments.

In the drawings:

Fig, 1 is a side elevation showing the new apparatus for practicing thenew method ci making vacuum tubes.

Fig. 2 is a plan view of the apparatus shown in Fig. 1.

Fig. 3 is a vertical cross-section taken on line 3--3 oi' Fig. i showingsubstantially diagrammatlcally the arrangement for heating andcirculat.. ing the heat in one of the baking ovens.

Fig. 4 is a vertical transverse cross-section taken on line 4-4 oi Fig.1 through another oven illustrating the arrangement for heating andcirculating the heat therein.

Fig. 5 is an enlarged side elevation with the portions broken awayshowing the pump dolly and illustrating some of the details ofconstruction and arrangement thereof.

All of the views in the' drawings show the apparatus in substantiallydiagrammatic form, many of the controls and electric circuits for thevarious heating and circulating elements being omitted for conveniencein illustration.

The apparatus for practicing the new method has a carriage or pump dollyprovided with a base 2 mounted on casters 3 and having a top 4 supportedon the base by means of corner posts or legs 5.

In the manufacture of vacuum tubes it is customary to rst provide aglass container or envelope and a stem. The various electron emissionand control elements are usually mounted on the stem in their assembledrelation with suitable circuit connection arranged through the stem sothat the tube may be included in the desired electric circuit. Someelements of some of these tubes are constructed and mounted in theenvelope and some are combined with the envelope in the constructionthereof. The stem is usually assembled in the glass envelope after thevarious elements have been assembled. The stem and envelope are securedtogether by a glass-blowing operation while the stem is usually providedwith a glass tube-through which the air and other gases in the tube maybe evacuated in completing the processing of the tube.

The tubes'are indicated diagrammatically by dthe numeral 6 and have thetubular extensions thereon connected in the first operation according tothe invention bya glass-blowing operation to the tubulations on pumpdolly l, as indicated at 1." Tubulations 'i are connected to manifold 8mounted in a suitable manner on the under side o1' top 4 of the pumpdolly.

The dolly carries a pumping system of conventional form used inevacuating the tubes connected with the tubulations. `A motor drivenfore pump dagrammatically indicated at 9 is mounted on base 2 of thedolly. Fore pump 9 may be constructed in any manner well known in theart and is adapted to provide a means for rapidly producing a fairvacuum within the tubes on the dolly. Fore pump 8 is connected bytubulation I0 to the discharge end of diffusion pump il. The inlet endof diffusion pump Il is con--I nected to manifold 8 by tubulation I2. Anionization gauge is indicated diagrammatlcally at I3 connected withtubulation I2 adjacent its connection with manifold 8.

The diffusion pump may'be any of the wellknown types of construction nowused in the art, such as the molecular disc type as diagrammaticallyillustrated in the drawings. Such a diffusion pump includes anevaporating vessel heated by an electric coil for a low vapor pressureiluid that is vaporized by the heat and projected through a jet nozzleand subsequently condensed and returned to the evaporating vessel. Theconstruction, operation and design of molecular diffusion pumps are wellknown in the art, particularly where they are constructed for condensingof the vapor by air cooling. It is well known that when such a pump isemployed in series with a fore pump as disclosed herein, that the systemis capable of producing a high vacuum of the order of 5 10-7 mm. ofmercury.

The ionization gauge is constructed and operated in a manner well knownin the art and further description thereof is not believed to benecessary. Suitable sockets and electrical connections are provided ondolly I so that the electric motor of the fore pump, the ionizationgauge and the heating elements of diffusion' pump II may be connectedwith a source of current supply by a suitable iiexible cable. Theseelectrical connections and the plugs on the dolly are not illustrated inthe drawings because they are merely the usual conventional meanswell-known in the art. It will be understood that the flexible cableconnection between the dolly and the source of current supply will beprovided with a suillcient length so that the dolly can be Plugged inand moved into the various stations at which the tubes are processed inaccordance with the method of this invention.

The first operation in processing vacuum tubes by the present inventionwill be the sealing of the tubes on the tubulations 'I of the pumpdolly. 'I'his is done by a glass blowing operation of wellknowncharacter. The dolly may then be moved on its casters after starting thefore and diffusion pumps to the first baking station indicated by thenumeral I5. The first baking station has an oven I6 of suitableconstruction, of rectangular form in cross-section, and open at oppositeends as illustrated in Fig. 3. Suitable oven doors I1 close the openends of the oven and are hingedly mounted on oven frame I8 also carryingthe oven. Frame I8 includes legs I9 arranged in spaced relation forsupporting the oven and doors in spaced relation above floor asufficient distance so that the pump dollymay be moved under the ovenduring processing of tubes thereon between the legs on opposite sides ofthe frame.

The upper surface of top 4 of pump dolly I can be moved under the bottomsurface oi' the oven between legs I9 with guide pins 2| engaged in andextending through slot 22 formed in longitudinally extending relationthrough the central portion of the bottom of the oven from end to end,as shown in Fig. 3. Guide pins 2| on pump dolly I have a largertransverse dimension 'than tubulations 'I so that in movement of thepump dolly under the oven from one endto the other tubes 6 thereon willproject into the oven above the bottom for treatment while the pumpdolly is moved underneath the oven and guide pins 2| prevent contactbetween tubulations I and the portions of the oven at opposite sides ofslot 22.

Electric heating units are mounted on the side walls n the oven asindicated diagrammatically at 23. These electric heating units are ofconventional form well-known in the art, are connected with a suitablesource of current supply with conventional type wiring, fuse and switchconstruction, not shown, while suitable temperature control means ofconventional form, not shown, is provided for automatically maintainingthe desired temperature in the oven. In order to maintain substantiallyuniform heat within the oven, heat circulating means is providedincluding a suitable conventional blower 24 having the outlet connectedwith a pair of conduits 25 extending longitudinally along opposite upperside portions inside the oven with a plurality of outlet nozzles 28directed downwardly, as shown in Figs. 1 and 3. An intake manifold 21 isconnected with the intake portion of blower 24 and has communicationwith the upper portion of the oven interior at one end, as shown inFig. 1. An electric motor 28 is mounted on the oven frame Il adjacentblower 24 and is connected for driving the blower so as to maintaincontinuous circulation of hot air in the oven to maintain asubstantially uniform temperature throughout the interior of the oven.Motor 2B is electrically connected with a suitable source of supplythrough a control switch and fuse system of conventional form, notshown.

In carrying out the invention, the oven is usually heated to the desiredtemperature before the baking operation at the baking station i5 isstarted. The baking station has the temperature in the oven maintainedsubstantially uniform during the processing of vacuum tubes inaccordance with the method used in carrying out this invention. When aplurality of tubes have been attached to a pump dolly as shown at theleft-hand side of Fig. 1 by the glass-blowing operation and the pumpoperated to provide the desired vacuum within the tubes to commence theprocessing operation of the present invention, the dolly is moved fromthe position shown at the left-hand side of Fig. 1 under the oven,through ilrst opening door I1 at the left-hand side of the oven, andengaging guide pins 2| in slot 22 in the bottom of the oven. When thepump dolly with the tubes mounted thereon is fully engaged within theoven, the left-hand door` I'I is closed and the processing at the bakingstation is begun.

An electrical processing control unit 30 is mounted on a suitable standhaving casters so that the unit is readily movable over floor 20. 'I'heunit 3|) is illustrated diagrammatically in Figs. 1 and 2 and has anelectric cable connection with pump dolly I of conventional form so thatthe desired electrical connections can be made with all of the apparatuson the pump dolly including the tubes, the ionization gauge, etc., foreffectively controlling and processing the tubes during their treatmentat the various stations in carrying out the method provided by thisinvention.

The oven, at baking station I5, may be of sufficient length to take twoor more dollies in aligned relation so that the tubes on the dollies maybe treated simultaneously and in a progressive manner for continuousprocessing of tubes particularly where the baking operation requiresmore time than processing operations at other stations. The tubes areheated for a substantial period of time in oven I6 in order to evolve orremove the occluded gases from the interior surfaces of the glass, metaland other parts. The tubes are constantly pumped to evacuate them duringthe heating operation in oven I6 in order to aid in the removal of theoccluded gases from the various parts of the tube. The duration of thebaking treatment in station I5 and the temperature at which the bakingis carried on may be varied with different types of tubes in obtainingdesired results.

When the heating and baking of the tubes is completed at station I5,right-hand door I'I as shown in Fig. 1, is opened and the dolly adjacentthereto is removed from under the oven and moved to the `treatmentstation indicated at II in Fig. 1. After pump dolly I is removed fromthe oven the right-hand door is closed so that the temperature in theoven at station I will be maintained at the desired heat for continuingthe treatment of tubes or other pump dollies in the oven.

When the dolly is positioned at station 3| as shown in Figs. 1 and 2,the tubes are then treated with high frequency current. A slide panel 32carries a plurality of high frequency coils 33 formed in half sectionsso that they may be engaged about tubes 8 by slidingthe slide panel intoposition on top of top 4 as illustrated in Fig. 1 at station 3|. Thesections of each high frequency coil are spaced apart a sulcientdistance to provide for the engagement of the sections about each tube5. When the high frequency coils are in the position shown in Figs. 1and 2, they will have a processing control unit 30 connected therewithto control the operation of the high frequency coils in processing thetubes. IThe high frequency coils provide for heating the metal partswithin the tubes such as the electrodes, stems, etc. The process iscarried on according to the type and size of tubes for a period of timethat may approximate in length that of the baking operation at stationI5, although the length of time for this high frequency treatment may bevaried to suit the type of tube being treated.

When the electrical treatment at station 3| has been completed the tubesare then given rurther electrical treatment While the tubes are heatedin an oven. This treatment involves the supplying of current to thefilaments and high voltage to the anodes and different voltages to otherelectrodes so that the anodes are bombarded by electron streams forevolving or eliminating gases in the material. This treatment is carriedon at station 35, indicated in Figs. 1 and 2.

Station 35 has an oven 36 somewhat smaller than oven I6 arranged with atransparent window 31 so that the electrical treatment of the tubeswithin the oven can be observed. Oven 36 is mounted on a framework 3Bwith the bottom mounted in spaced relation above the floor 20 at such adistance that a pump dolly I can be moved under the oven with the topface of top 4 in contiguous relation to the bottom of the oven. Frame 38includes a leg structure 39 arranged to provide spaced legs so that pumpdollies can be moved between the legs underneath oven 36. is providedwith a longitudinal slot 40 extending from end to end thereof while theopen ends of oven 36 are closed by hinged doors 4|. Hinged doors 4|provide for the convenient insertion and removal of the tubes in oven 36by moving the pump dollies underneath the oven with guide pins 2|engaged in slots 40. A pump dolly is moved into oven 35 at station 35from the left-hand side. as shown in Fig. 1, the left-hand door beingopened for thispurpose and after the dolly is moved under the oven withthe tubes in the oven, door 4| is closed.

The oven is heated electrically by suitable heating elements indicatedgenerally in Fig. 4 at 42, suspended in a heater casing 43 mounted onframework 38 above the oven and having the lower end of the heatercasing provided with a passage communicating with the upper portion ofthe oven. The upper left-hand portion of heater casing 43, as shown inFig. 1, is connected with the intake of blower 44 driven by an electricmotor 45 mounted on bracket structure 46 carried by framework 38. Theoutlet of blower 44 is connected with a manifold 41 in the upperinterior portion of oven 35. Manifold 41 has Oven 3B sections arrangedat opposite side portions oi the oven in longitudinally extendingrelation and is formed with a plurality of downwardly projectingdischarge nozzes 48. Hot air for heating the oven to the desiredtemperature which is usually less than that of the oven at station |5 iscirculated through the oven by blower 44 driven by motor to maintain theheat in the oven uniform for uniformly heating all parts of the tubesbeing processed to the desired temperature. While the tubes are beingheated in the oven at station 35 they are connected to an electricalprocessing control unit 30, one of which is shown at station 35 forcontrolling the heating of the laments and voltage on the severalelectrodes in order to control the bombardment of the electrodes by theelectron streams within the tube for driving out the gases in theelectrodes. This operation is carried on for a desired length of time aswell-known in the art, the operator belng'able to watch the tubesthrough window 31 in controlling the processing thereof.

If X-ray tubes are to be treated at station 35 it is usually preferableto provide a lead shield for the oven. It may also be desirable toenclose the space below the oven between the legs 38 with a suitablecasing arranged with lead shields to protect the operator from theX-i'ays during the processing of the tubes. This will provide a completeenclosure for the oven and the frame 38 extending from the floor up tothe top of the frame while the doors 4| will be extended to the iloor inorder to control the openings at the ends of the oven and the spacebelow to provide for the movement of the dollies from the left-hand endof the oven at station 35 into the casing and then after the treatmentis completed to move the dollies out from the right-hand end. Thiscasing enclosing the whole frame is not disclosed in the drawings butfrom the disclosure in the drawings it will be readily understood by oneskilled in the art how this casing for protecting an operator againstX-rays may be readily provided. The window 31 will be formed of leadglass so as to protect the operator observing the condition of treatmentof X-ray tubes.

Depending on the type of tube being produced. it may be desirable togive the tubes further treatment after they are removed from the oven atstation 35. For this purpose the dolly mounting the tubes is moved tothe station indicated at in Figs. 1 and 2 where an electrical processingcontrol unit 30 may be connected thereto and Iurther electricalprocessing carried on to complete the treatment of the tubes. When thistreatment is completed at station 50, a glass-blowing operation is thencarried on to seal off tubulations 1 for removing the tubes from thedolly in completely treated form so they may be nally tested andsubsequently prepared for commercial use. One of the treatmentscarried-on at station 50 for example, may be special lament in additionto the sealing off operation on tubulations 1.

With the apparatus described above the treatment of vacuum tubes can becarried on in which the baking, high frequency heating and electricaltreatment consume about the same length of time so that a seriesofdollies with the tubes mounted thereon may be successively moved fromone station to the other in the successive treatments. In this way thebaking and electrical treatment of the tubes may be carried oncontinuously for continuous production of tubes as rapidly as thetreatment can be completed. Several dollies may be placed under over I8so that when the treatment at station I5 requires more time thantreatments at the other stations, the baking operation may be carried onsimultaneously on a greater number of tubes in order to provide forcontinuous treatment of a limited number of tubes at all of the stationsto maintain a desired quantity of production and operate the apparatusat full capacity in production.

By placing the pumping units on the pump dolly I, the pumping operationcan be carried on in advance of the baking treatment at station I5 forthe desired length of time in order that the .tubes may be processed inan efficient manner. The present process and apparatus provides anadvantageous method of treating vacuum tubes for increasing efficiencyand lowering cost in production because very little time is lost inthebaking treatment of the tubes as compared with previous methods. Theovens at both stations I5 and I5 may be readily maintained atasubstantially constant temperature for carrying on the bakingoperations at different temperatures and the dollies with the tubesthereon may be quickly and conveniently inserted and removed from eachof the ovens for this treatment Without material loss of heat. At nostage in the processing of tubes according to the present invention isit necessary to allow the ovens to cool down in order to carry on partof the treatment of the tubes. This gains a particular advantage in theoperation of the present process and apparatus in the manufacture oftubes, saving heating costs, time and labor.

I'he apparatus provided by this invention also utilize operators thathave considerably less skill than have been heretofore required in theart. For example, the sealing on and sealing oil.' operations of thetubes done by a glass-blowing operation, may be done by an operatorskilled in these particular operations while another opera' tor willcarry on the baking treatment at the station I5. 'I'hese operators willonly be required to have sufficient skill to perform one of theseoperations instead of both, so that operators may be trained for eachdifferent operation. Still another operator will be utilized forcarrying on the high frequency treatment of the tubes at station 3|. Itis only necessary that the operator be skilled in the high frequencytreatment of the tubes at the station 3| and likewise another operatorskilled in the operations carried on in processing tubes at the station35 will be more efficient and will be able to carry on the operation onsuccessive tubes with greater uniformity so that the tubes produced bythe present invention will be more uniform in their operating eillciencythan when they are produced by methods heretofore used in whichdifferent operators would completely process different groups of tubesand due to the varying skill of the operators the tubes would vary to asubstantial extent.

In addition operators may be secured that are particularly adept foroperating the processing of the tube at one station as distinguishedfrom another and the talents of the operator thereby used to betteradvantage in obtaining greater efficiency in manufacturing moreeillcient tubes.

This invention therefore provides for the more rapid training ofoperators in the different operations so that more highly skilledoperators can be trained for carrying on the sealing on of the tubes,the baking, high frequency treatment, etc.

in a much more eicient manner than has heretofore been possible.

The invention also provides for the continuous processing of tubesthrough the various stations with the maintenance of uniform conditionsof operation in all of the stations and by this method more eflicientand uniform processing of vacuum tubes is obtained in which the tubesproduced will also be more uniform.

The invention claimed is:

l. Apparatus for manufacturing vacuum tubes comprising a carriage havinga flat top portion, a plurality of tubulations extending through saidtop portion in aligned spaced relation for mounting a vacuum tube oneach tubulation for processing, a slide panel detachably and slidablymounted on said top portion, a plurality of coils, one for eachtubulation and tube thereon mounted on said slide panel, each coil beingformed in sections mounted in spaced complementary relation to receive atube and tubulation between the sections in sliding said slide panel onsaid top portion for engaging said coils about tubes on saidtubulations, and means on said carriage and for connection with saidcoils for processing tubes mounted on said tubulations.

2. Apparatus for manufacturing vacuum tubes comprising a frame, an ovenbody formed oi' insulating material having a hollow rectangular form incross-section, open at both ends and formed with a longitudinal slot inthe bottom opening through both ends, means attaching said body to saidframe for support in spaced relation above a licor, doors lclosing bothopen ends of said body, heating units mounted on the inner side walls ofsaid body intermediate the upper and lower edges and extending from endto end thereof, a pair of nozzle conduits, each mounted at one side ofthe body on the inner face of the top wall vadjacent one side wall andextending from end to end thereof, each nozzle conduit having aplurality of nozzles extending downwardly therefrom for directing air instreams downwardly toward the adjacent heating unit, a blower connectedfor circulating air through said conduits and outwardly from saidnozzles, and an air return passage from the interior of said body tosaid blower, whereby heat may be distributed through said body in asubstantially uniform manner for baking vacuum tubes.

3. Apparatus for manufacturing vacuum tubes comprising a frame havingsupporting legs spaced to provide a passage therethrough along thesupporting floor, an oven body mounted in said frame above said floor,said oven body being open at both ends and having a slot in the centralbottom wall opening through the ends, doors closing both ends adapted tobe opened for moving material into and out of the oven body, means foruniformly heating said oven body, and a carriage movable under said bodythrough said passage having tubulations for carrying vacuum tubes forprocessing in said oven with said tubulations extending through saidslot, and guide pins on said carriage for engagement in said slot andwith said body for guiding said carriage through said passage andprotecting said tubulations from breakage during moving through saidslot.

MARSHALL P. WILDER.

